package com.csp.mingyue.common.mybatis.page;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.core.metadata.OrderItem;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.csp.mingyue.common.core.exception.ServiceException;
import com.csp.mingyue.common.mybatis.utils.SqlUtil;
import io.swagger.v3.oas.annotations.media.Schema;
import lombok.Data;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/**
 * 分页查询通用类
 *
 * @author Strive
 * @date 2023/9/6 13:52
 */
@Data
@Schema(description = "分页查询通用类")
public class PageCommon implements Serializable {

	private static final long serialVersionUID = 1L;

	@Schema(description = "分页大小")
	private Integer pageSize;

	@Schema(description = "当前页数")
	private Integer pageNum;

	@Schema(description = "排序列")
	private String orderByColumn;

	@Schema(description = "排序的方向 desc 或者 asc")
	private String isAsc;

	/**
	 * 当前记录起始索引 默认值
	 */
	public static final int DEFAULT_PAGE_NUM = 1;

	/**
	 * 每页显示记录数 默认值 默认查全部
	 */
	public static final int DEFAULT_PAGE_SIZE = Integer.MAX_VALUE;

	public <T> Page<T> build() {
		Integer pageNum = ObjectUtil.defaultIfNull(getPageNum(), DEFAULT_PAGE_NUM);
		Integer pageSize = ObjectUtil.defaultIfNull(getPageSize(), DEFAULT_PAGE_SIZE);
		if (pageNum <= 0) {
			pageNum = DEFAULT_PAGE_NUM;
		}
		Page<T> page = new Page<>(pageNum, pageSize);
		List<OrderItem> orderItems = buildOrderItem();
		if (CollUtil.isNotEmpty(orderItems)) {
			page.addOrder(orderItems);
		}
		return page;
	}

	/**
	 * 构建排序
	 *
	 * 支持的用法如下: {isAsc:"asc",orderByColumn:"id"} order by id asc
	 * {isAsc:"asc",orderByColumn:"id,createTime"} order by id asc,create_time asc
	 * {isAsc:"desc",orderByColumn:"id,createTime"} order by id desc,create_time desc
	 * {isAsc:"asc,desc",orderByColumn:"id,createTime"} order by id asc,create_time desc
	 */
	private List<OrderItem> buildOrderItem() {
		if (StrUtil.isBlank(orderByColumn) || StrUtil.isBlank(isAsc)) {
			return null;
		}
		String orderBy = SqlUtil.escapeOrderBySql(orderByColumn);
		orderBy = StrUtil.toUnderlineCase(orderBy);

		String[] orderByArr = orderBy.split(StrUtil.COMMA);
		String[] isAscArr = isAsc.split(StrUtil.COMMA);
		if (isAscArr.length != 1 && isAscArr.length != orderByArr.length) {
			throw new ServiceException("排序参数有误");
		}

		List<OrderItem> list = new ArrayList<>();
		// 每个字段各自排序
		for (int i = 0; i < orderByArr.length; i++) {
			String orderByStr = orderByArr[i];
			String isAscStr = isAscArr.length == 1 ? isAscArr[0] : isAscArr[i];
			if ("asc".equals(isAscStr)) {
				list.add(OrderItem.asc(orderByStr));
			}
			else if ("desc".equals(isAscStr)) {
				list.add(OrderItem.desc(orderByStr));
			}
			else {
				throw new ServiceException("排序参数有误");
			}
		}

		return list;
	}

}
